Pan-Cancer Analysis of Microfibrillar-Associated Protein 2 (MFAP2) Based on Bioinformatics and qPCR Verification

MFAP2 has been reported to play an oncogenic role in several types of human cancers. However, the expression profile of MFAP2 in various cancers and its impact on prognosis and immune infiltration remain unclear. In this study, the mRNA expression and protein expression of MFAP2 in normal tissues, tumor cell lines, and 33 malignant tumor tissues were analyzed comprehensively using Genotype-Tissue Expression (GTEx), Cancer Cell Line Encyclopedia (CCLE), and The Cancer Genome Atlas (TCGA), Oncomine and UALCAN databases, and the expression of MFAP2 in different grades and stages of cancers was assessed using Gene Expression Profiling Interactive Analysis 2 (GEPIA2) and Tumor and Immune System Interaction Database (TISIDB). In general, MFAP2 showed distinct expression in most tumor and normal tissues, closely associated with higher tumor grade, higher tumor stage, and poor survival in multiple cancers. A search of the UALCAN database and the cBioPortal database revealed that this difference in mRNA level expression could be partly attributed to abnormal DNA methylation and mutations at the genomic level. In addition, MFAP2 expression was also associated with tumor mutation burden, microsatellite instability, and neoantigens in different cancer types. More importantly, the TIMER and TISIDB databases also showed that MFAP2 levels were significantly correlated with immune infiltration abundance and immune-related gene markers, as well as ESTIMATE scores. By qPCR, MFAP2 expression was validated in four kinds of tumor tissue samples. The present study combined several databases and performed a pan-cancer analysis of the expression profile, methylation, and mutation for MFAP2 and its implications for prognosis and immune infiltration, suggesting that MFAP2 could contribute to malignant properties of many tumors. MFAP2 may be an important biomarker with prognostic value and has the potential to be a target for tumor immunotherapy.